Semiconductors devices such as memory devices reside in many computers and electronic products. A typical memory device has many memory cells to store data.
The data in a memory cell is represented by a charge. The charge loses its value over time due to leakage and other factors, causing the data to become invalid. To retain the validity of the data, a typical memory device frequently performs a refresh operation at a specific refresh interval to restore (or refresh) the charges to their original values.
In some cases, a change in the temperature causes a conventional memory device to perform the refresh operation more frequently than necessary. For example, when the temperature deceases, a conventional memory device may perform more refresh operation than that at a higher temperature. Thus, power is wasted.